WO2023074480A1

WO2023074480A1 - Gas analysis device and control method

Info

Publication number: WO2023074480A1
Application number: PCT/JP2022/038848
Authority: WO
Inventors: 博文長尾; 伸一三木; 直樹高橋; プラカッシスリダラムルティ
Original assignee: アトナープ株式会社
Priority date: 2021-10-29
Filing date: 2022-10-19
Publication date: 2023-05-04
Also published as: JPWO2023074480A1

Abstract

A gas analysis device (1) comprises: a sample chamber (12) into which flows a sample gas (9) to be measured, the sample chamber being provided with a dielectric wall body structure; a plasma generation mechanism (13) that generates a plasma (19) inside a pressure-reduced sample chamber by using an electric field and/or a magnetic field through the dielectric wall body structure; a gas input device (5) configured such that only the sample gas flows from a process chamber (102) into the sample chamber; a first detector (20) that filters ionized gas in the generated plasma and detects components in the plasma; and a second detector (80) that analyzes the light emission of ions in the plasma of the sample chamber and can output a second detection result (52) synchronized with a first detection result (51) of the first detector.

Description

Gas analyzer and control method

The present invention relates to a gas analyzer and its control method.

Japanese Patent Application Laid-Open No. 2016-27327 discloses that in a glow discharge optical emission spectrometry (GD-OES), a sample holder has an electrode (second electrode) having a sample fixing surface, and a sample fixing surface. and an outer cylinder portion and an inner cylinder portion (abutting portion). With the sample separated from the opening of the glow discharge tube, the open end of the inner cylindrical portion is brought into contact with the peripheral edge of the opening. The inside of the communicating glow discharge tube, the outer cylindrical portion, and the inner cylindrical portion is depressurized, and argon gas is supplied. Next, move the inner cylinder with respect to the outer cylinder to bring the sample closer to the tip of the cylindrical part (end) of the anode (first electrode) of the glow discharge tube, and let the coolant flow through the channel (cooling part). It describes cooling the sample and applying a voltage to the electrodes to perform glow discharge optical emission spectroscopy.

There is a demand for gas analyzers that can detect components contained in sample gases by ionizing them in a more stable or more accurate manner.

One aspect of the present invention is a sample chamber having a dielectric wall structure, into which a sample gas to be measured flows, and an electric field and/or a magnetic field via the dielectric wall structure. a plasma generation mechanism configured to generate a plasma in the sample chamber, a gas input device configured to allow only the sample gas from the process to flow into the sample chamber; and a second detector that analyzes the emission of ions in the plasma in the sample chamber and outputs a second detection result synchronized with the first detection result of the first detector A gas analyzer having a detector. In this gas analyzer, plasma, which serves as an ion source for the first detector, can be subjected to emission analysis by the second detector. For this reason, a common ionized sample can be synchronously, i.e., simultaneously, in parallel, or in different ways, with a presettable limited time interval (latency) or stagger specific to this gas analyzer. It can be analyzed and data for analysis can be generated that correlates detection results from these different methods.

Typically, the first detection result includes a mass spectrum acquired by time division (time lapse), that is, acquired serially (sequentially) because it is necessary to change the detection conditions with the filter. . On the other hand, the second detection result includes an emission spectrum obtainable in parallel by spectroscopy. This gas analyzer includes a sample chamber for generating a common plasma, which serves as an ion source and a light source, separately from the process, and includes first and second detectors whose routes are fixed in advance with respect to the sample chamber. include. Therefore, the first serial detection result and the second parallel detection result for the common plasma generated in the sample chamber can be synchronously acquired, and generated and output as analysis data in association with each other. can do. For this reason, for example, by checking the variation of the second detection result obtained in parallel during the time interval in which the first detection result obtained serially is obtained, the first detection result can be obtained. It becomes possible to verify that the information is from the plasma maintained under the same conditions, for example, the process under the same conditions, and obtain more reliable analysis results.

Further, by generating microplasma in the sample chamber of the gas analyzer, the volume of the common ion source and light emission source to be detected can be reduced, and the first detection result and the second detection result for the same target can be obtained. Obtainable. Furthermore, it is also possible to limit the serially obtained mass spectrum to a region of interest (ROI). In this way, while confirming a wide range of information, it is possible to obtain more accurate analysis results for the ROI at short time intervals, including temporal fluctuations.

The gas analyzer is a first analyzer that analyzes the sample gas based on the first detection result and the second detection result synchronized with the first detection result with a time interval defined by the gas analyzer. may have Due to the difference in spectral interference between the first detection result and the second detection result, a more accurate analysis is possible by cooperating the detection results.

Another aspect of the present invention is a method of controlling a system having a gas analyzer, comprising a first detection result of a first detector and a second detection result of a second detector; including synchronous output of Synchronously outputting a first detection result including a mass spectrum obtained by time division (serial) and a second detection result including a (parallel) emission spectrum synchronously comparable with the first detection result. may include outputting in association with the detection result of The mass spectrum may include a mass spectrum restricted to a region of interest (ROI).

Another aspect of the present invention is a program (program product) for controlling a system with a computer by the method of controlling a system having the above gas analyzer. The program contains instructions for carrying out control of the system. The program may be recorded on an appropriate computer-readable medium and provided.

1 is a block diagram showing a schematic configuration of a process monitoring system including a gas analyzer; FIG. The figure which shows an example of the data for analysis. Flowchart outlining process monitor operation. 4A-4D illustrate different examples of process monitoring systems including gas analyzers. FIG. 4 shows yet another example of a process monitoring system including a gas analyzer;

Embodiment of the invention

FIG. 1 shows a schematic configuration of a process monitoring system 100 as an example of a system including the gas analyzer 1. A gas analyzer 1 analyzes a sample gas 9 supplied from a process chamber 101 in which a plasma process 102 is performed. The plasma process 102 carried out in the process chamber 101 is typically a step of forming various types of films or layers on a substrate or etching a substrate, and is a CVD (Chemical Vapor Deposition) process. ) or PVD (Physical Vapor Deposition). The plasma process 102 is not limited to processes related to semiconductor manufacturing, and may be processes for laminating various types of thin films using optical components such as lenses and filters as substrates.

For example, in semiconductors, in recent years, semiconductor chip structures have become three-dimensional due to demands for increased memory capacity, improved logic speed, and reduced power consumption. As a result, semiconductor process control is challenged by more complex processes, demands for atomic-level quality, and increased costs required for measurement and monitoring. Gas monitoring, including reactants and by-products, is important for process matching, transition point measurement during deposition, and etching endpoint detection. , OES), it is difficult to monitor the process comprehensively. On the other hand, residual gas spectrometers and mass spectrometers with ion sources that employ ordinary hot filaments have a problem of lifetime due to damage caused by semiconductor gas.

In the process monitoring system 100 using the gas analyzer 1 of this example, it is possible to provide innovative process control by performing real-time monitoring even under harsh environments and providing highly reliable measurement results. The gas analyzer 1 functions as a total solution platform developed for the purpose of dramatically improving the throughput in semiconductor chip manufacturing and maximizing the yield rate. As described above, the gas analyzer 1 of this example can be directly connected to the chamber 101 because it has a very small installation area. In addition, a standard protocol that is currently mainly used in semiconductor manufacturing process equipment, such as the Either Cat protocol, can be mounted on the PLC 50 and integrated into the process equipment control system 100.

The gas analyzer 1 includes an ionization device 10 that generates ions (ion flow) 17 of a sample gas 9 and a sensor group that detects ions supplied from the ionization device 10 or generated in the ionization device 10. sensor suite, analysis group) 90. The ionization device 10 comprises a plasma generation unit (plasma generator) 11 for generating a plasma 19 of the sample gas 9 to be measured supplied from the process 102 via the sample input 3a. The plasma generation unit 11 comprises a dielectric wall structure 12a into which a sample gas 9 to be measured flows (sample chamber) 12, and through the dielectric wall structure 12a a high-frequency electric field and/or a magnetic field. , a high-frequency supply mechanism (RF supply mechanism, plasma generation mechanism) 13 for generating plasma 19 in a depressurized sample chamber 12, and a plasma controller 16 for controlling the frequency and power of the high-frequency wave. A plasma 19 is supplied as an ion stream 17 from an opening 18 provided at one end of the sample chamber 12 to a first detector 20 which will be described later. The gas analyzer 1 includes a gas input device 5 configured to flow into the sample chamber 12 only the sample gas 9 from the process chamber 101 in which the plasma process 102 is performed.

The gas analysis sensor group 90 includes a first detector 20 that filters ionized gas in the plasma 19 supplied as ions (ion flow) 17 to detect components in the plasma, and a second detector 80 for analyzing (spectroscopic analysis) the emission of the ions of . An example of the first detector (first sensor, first detector, first measuring device) 20 is a mass spectrometric detector (mass spectrometer, MS). The first detector 20 comprises a filter unit (mass filter, quadrupole filter in this example) 25 for filtering the ionized sample gas (sample gas ions) 17 by mass-to-charge ratio, and detects the filtered ions. and a detector 26 that The gas analyzer 1 further includes a vacuum container (housing) 40 containing the filter unit 25 and the detector 26, and an exhaust system 60 that maintains the inside of the housing 40 under an appropriate negative pressure condition (vacuum condition).

The exhaust system 60 of this example includes a turbomolecular pump (TMP) 61 and a roots pump 62 . The exhaust system 60 is of the split-flow type that also controls the internal pressure of the sample chamber 12 of the plasma generator 11 . Of the multi-stage TMP 61 of the exhaust system 60, the stage that has a negative pressure suitable for the internal pressure of the chamber 12 or the input of the roots pump 62 communicates with the chamber 12 so that the internal pressure of the chamber 12 is controlled.

Therefore, the gas analyzer 1 of this example has an exhaust device 60 for exhausting gas from the sample chamber 12, and the exhaust device 60 bypasses the first detector 20 and exhausts gas from the sample chamber 12 as a first exhaust path. 65 and a second exhaust path 66 that exhausts through the first detector 20 . By providing a first exhaust path 65 that bypasses the first detector 20 from the sample chamber 12 and exhausts the sample, the sample chamber 12 is supplied with a sample gas flow rate separate from the gas flow flowing to the first detector 20 for filtering. It becomes possible to guide the gas 9 and control the internal pressure of the sample chamber 12 . Therefore, the amount of gas flowing through the first detector 20 can be stabilized, and the detection accuracy can be stabilized. On the other hand, since sufficient sample gas 9 can be drawn into the sample chamber 12 from the process via the gas input device 5, it is possible to provide the gas analyzer 1 capable of monitoring the state (variation) in the process chamber 101 in real time.

The mass filter 25 of this example includes four cylindrical or cylindrical electrodes 25a with inner hyperbolic surfaces to form a hyperbolic electric field for mass-to-charge ratio filtering. The quadrupole-type mass filter 25 may be one in which a large number of, for example, nine cylindrical electrodes are arranged to form a matrix (array) so as to form a plurality of quasi-hyperbolic electric fields. . Detector 26 includes a Faraday Cap and a Secondary Electron Multiplier, which may be used in combination or interchangeably. Detector 26 may be of other types, such as a Channel Electron Multiplier, Microchannel Plate, or the like.

The plasma generation device 11 of this example includes a sample chamber 12 for plasma generation that is integrally incorporated inside a housing 40 . The outer shell of the chamber 12 is made of Hastelloy, an insulated cylindrical electrode is inserted therein, and plasma 19 is generated therein. Only the sample gas 9 flows into the evacuated sample chamber 12 from the sample input 3a through the gas input device 5 from the process chamber 101 in which the process 102 to be monitored is performed, and a plasma 19 is formed inside the sample chamber 12. be done. That is, in the plasma generator 11, the analysis plasma 19 is generated only from the sample gas 9 without using an assist gas (support gas) such as argon gas. The wall 12a of the sample chamber 12 is made of a dielectric member (dielectric), for example quartz, aluminum oxide (Al ₂ O ₃ ) and silicon nitride (SiN ₃ ). It is a light-transmitting dielectric with high durability.

In the plasma generation device 11, a mechanism (RF supply mechanism) 13 that specifically generates plasma generates an electric field and/or A plasma 19 is generated by the magnetic field. An example of the RF supply mechanism 13 is a mechanism that excites the plasma 19 with RF (Radio Frequency) power. Examples of the RF supply mechanism 13 include inductively coupled plasma (ICP), dielectric barrier discharge (DBD), and electron cyclotron resonance (ECR). . These types of plasma generating mechanisms 13 may include a radio frequency power source and an RF field forming unit. A typical RF field shaping unit includes coils arranged along the sample chamber 12 . The plasma generation device 11 of this example includes a function of igniting by changing the matching state by changing the frequency of the RF field. For example, plasma can be generated and maintained by applying pulsed high-frequency power to ignite plasma and then transitioning to a steady operating state. The plasma generator 11 may be of a type in which an inductively coupled plasma (ICP) is formed by an assist gas such as argon gas and ionized by introducing a sample gas. is desirable, and the assist gas may be dispensed with by generating microplasma.

The internal pressure of the sample chamber 12 of this example may be a pressure at which plasma is likely to be generated, for example, in the range of 0.01-1 kPa. When the internal pressure of the process chamber 101 is controlled at about 1-several 100 Pa, the internal pressure of the sample chamber 12 may be controlled at a lower pressure, for example, about 0.1-several 10s Pa, 0.1 Pa or more, Alternatively, it may be controlled to 0.5 Pa or more, 10 Pa or less, or 5 Pa or less. For example, the inside of the sample chamber 12 may be evacuated to about 1-10 mTorr (0.13-1.3 Pa). By maintaining the pressure in the sample chamber 12 at the above level, it is possible to generate the plasma 19 at a low temperature using only the sample gas 9 . The sample chamber 12 may be small enough to generate the plasma 19, for example, a chamber having a total length of 1 to 100 mm and a diameter of 1 to 100 mm, and may be a chamber (miniature chamber) of several mm to several tens of mm. may By reducing the capacity of the sample chamber 12, it is possible to provide the gas analyzer 1 excellent in real-time performance. Sample chamber 12 may be cylindrical.

The gas analyzer 1 includes an ionization device 10 and an electron ionization device (filament ionization device) that ionizes (electron ionizes) the sample gas 9 to be measured, which is supplied from the sample input 3b from the process 102 via the gas input device 5, by electron impact (electron ionization). , EI ion source) 15 . The EI ion source 15 operates in a high vacuum, and even when the process in the process chamber 101 to be monitored is in a high vacuum and conditions are such that it is difficult to generate the microplasma 19, the EI ion source 15 operates at the ultimate pressure of the gas analyzer 1, and furthermore, performs sensitivity correction. can be used for the purpose of The gas supply device 5 comprises a connecting pipe 5c connected to the process chamber 101, a valve 5a controlling the flow of the sample gas 9 between the connecting pipe 5c and the sample input 3a for plasma ionization, the connecting pipe 5c and the EI and a valve 5b controlling the flow of sample gas 9 to and from the sample input 3b for ionization. By switching the

valves

5a and 5b by the process controller 105, the detection mode (measurement mode) of the gas analyzer 1 can be switched automatically or manually. The EI ion source 15 is provided between the sample input 3b and the filter unit 25, and is in a common flow path with the ion flow 17 from the plasma (microplasma) 19 formed in the sample chamber 12. facing. Thus, the EI ion source 15 is also capable of electron ionizing the sample gas 9 from the gas input device 5 and ionizing the gas from the sample chamber 12 (the plasma 19 derivative gas) to the first detector 20 . It is also possible to supply to

In one embodiment, when the process controller 105 executes the highly reactive process 102 in a state where the internal pressure of the process chamber 101 is high, e.g. Gas 9 is supplied. The controller 50 of the gas analyzer 1 generates a plasma (microplasma) 19 of the sample gas 9, which is different from the process 102, from the sample gas 9, extracts ions 17 from the microplasma 19, and performs mass spectrometry. At this time, the EI ion source (filament) 15 is not lit and the valve (port) 5b is closed. When the internal pressure of the process chamber 101 is low, for example, when measuring the ultimate pressure, the plasma side port (valve) 15a is closed and the EI side port 5b is opened to supply the sample gas 9 and light the filament ( The internal state of the process chamber 101 may be monitored by activating the EI).

The gas analyzer 1 may include an energy filter 28 arranged between the EI ionization source 15 and the filter 25 . The energy filter 28 may be a Bessel-Box, a CMA (Cylindrical Mirror Analyzer), or a CHA (Concentric Hemispherical Analyzer). The Bessel box type energy filter 28 is composed of a cylindrical electrode, a disc-shaped electrode (same potential as the cylindrical electrode) placed in the center of the cylindrical electrode, and electrodes placed at both ends of the cylindrical electrode. The electric field created by the potential difference Vba and the potential Vbe of the cylindrical electrode act as a band-pass filter that allows only ions having a specific kinetic energy to pass through. In addition, soft X-rays generated during plasma generation and light generated during gas ionization can be prevented from directly entering the ion detector (detector) 26 by the disc-shaped electrode arranged at the center of the cylindrical electrode. , can reduce noise. In addition, the energy filter 28 can also eliminate ions and neutral particles that are generated in the ion generation section or outside and that enter the filter unit 25 parallel to the central axis, so that the structure is such that their detection can be suppressed. there is

An example of the second detector (detector, analyzer, sensor) 80 is an emission spectrometer detector, typically an emission spectrometer (optical emission spectrometer, OES, atomic emission spectrometry , AES). An example of OES 80 is a receiving or collecting lens, such as an objective lens, attached to translucent dielectric wall structure 12a of sample chamber 12, in parallel with RF feed 13 or coaxial with RF feed 13's coil. It includes an optical element 81 , an optical fiber 82 that guides light from the light collecting element 81 , and a spectroscopic analysis unit (OES unit, OES detector) 85 that spectroscopically analyzes the light supplied by the optical fiber 82 . Spectroscopic analysis unit 85 may be any type of detector employed in OES 80, such as sequential or multi-channel.

The gas analyzer 1 includes a control module 30 that controls each module of the analysis unit 20 under the PCL 50. The control module 30 includes a control module 35 for controlling the mass spectrometer 20, a unit 31 for controlling the extraction of the plasma 19, a unit 32 for controlling the electron ionizer 15, and the RF and DC voltages for the mass filter 25. A filter control function (filter control device) 33 that selects a region (region of interest, ROI) of an object (ion) to be controlled and measured by the filter 25, and a function (intensity detection device) 34. The control module 35 may include a function of controlling the potential of the lens group of the mass spectrometer 20, a function of controlling the potential of the energy filter 28, and the like. The control unit 32 of the EI unit 15 may include filament control functions to control filament current and voltage.

A PLC (control device) 50 that controls the gas analyzer 1 includes computer resources such as a CPU 56 and a memory 55, and controls the gas analyzer 1 by loading and executing a program (program product) 59. The program 59 includes instructions for implementing and operating each function described below in the PLC 50 . The PLC 50 generates synchronized analysis data 53 by associating the first detection result 51 of the first detector 20 with the second detection result 52 of the second detector 80. Including functions as The program 59 can be recorded on a computer-readable medium and provided.

FIG. 2 schematically shows the first detection result 51 and the second detection result 52. An example of the first detector 20 is a Mass Spectrometer (MS) that measures the mass and intensity of ionized elements in the plasma. An example of the first detection result 51 is the intensity to mass-to-charge ratio (m/z). An example of second detector 80 is an optical detector (OES) that measures the wavelength and intensity of light emitted from elements excited in the plasma. An example of the second detection result 52 is intensity versus wavelength. Features (advantages) of the first detector (MS) 20 over the second detector (OES) 80 include high sensitivity, wide dynamic lens, multi-element quantitative measurement, isotope ratio measurement, and spectral simplicity. etc. Disadvantages include reduced resolution due to mass spectral interferences.

That is, MS20 is superior in terms of sensitivity, and while OES80 is about sub-ppb, MS20 can detect sub-ppt. On the other hand, in terms of measurement time, since the output of the OES 80 is an emission spectrum, the second detection result 52 can basically be obtained with the sensitivity of the spectrometer, and the number of elements (components) contained in the sample gas 9 increases. There is no conversion to the measurement time (detection time). Further, the second detection result 52 includes information on all elements (components) as long as the spectrum can be obtained. In the MS 20, since the conditions of the filter 25 are changed in a time-division manner for measurement, the measurement time depends on the number of elements and mass numbers to be measured, and the first detection result 51 includes the measurement target (measured mass number ) are included. In terms of spectral interference, MS20 cannot separate elements (components) with the same mass-to-charge ratio m/z, and OES80 has difficulty separating elements (components) with spectra having the same or close frequencies. .

Therefore, focusing on the measurement time, as shown in FIG. 2, the first detection result 51 includes a mass spectrum acquired by time division (lapse of time), that is, acquired serially (sequentially). That is, when spectrum acquisition is started at time t1 (51a), as shown at time t2, the mass-to-charge ratio m/z is searched in order (51b), and at time tn, the desired mass-to-charge m/z (region of interest , ROI) 51r can be obtained (mass spectrum 51c). Even with a relatively high-speed MS, it takes about 1 ms to measure with filter conditions set for one m/z, and it is possible to measure 1000 points (m/z) in one second. The measurement time is greatly increased compared to . Furthermore, when trying to improve the detection sensitivity (quantitative measurement sensitivity), it consumes time because the measurement time at one point increases. On the other hand, if time is spent, highly accurate measurement is possible, and highly sensitive measurement results (detection results) 51 can be obtained by measuring the components limited to the desired ROI.

On the other hand, the second detection result 52 includes an emission spectrum that can be acquired instantaneously (on the order of ms or less) at least in parallel with the first detection result 51 by spectroscopy. Therefore, the

second detection results

52a, 52b and 52c obtained at times t1, t2 and tn are identical if the state of the microplasma 19 does not change. Therefore, the reliability of the serially obtained first detection result 51 can be ensured by synchronizing and associating the second detection result 52 and the first detection result 51 obtained in parallel. Synchronization between the first detection result 51 and the second detection result 52 mainly involves two latencies unique to this gas analyzer 1 .

One factor that causes the time difference is that the first detection result 51 is the result of filtering the ion flow 17 supplied from the microplasma 19 by the filter 25, and the ions need to physically reach the detector 26. is. That is, when the microplasma 19 fluctuates, it takes time for the ions to physically reach the detector 26 of the first detector 20 to detect the fluctuation, and the state of the plasma 19 is different from the time difference. (latency).

On the other hand, the second detection result 52 is the emission spectrum, and if there is a change in the state of the microplasma 19, it appears in the detection result without any time lag. However, in the gas analyzer 1, the microplasma 19 generated in the fixed sample chamber 12 is an object to be inspected by the first detector 20 and the second detector 80, and the first detection result 51 and The time difference from the second detection result 52 can be set in advance as a unique value of the gas analyzer 1 . Therefore, the time difference between the first detection result 51 and the second detection result 52 is known in the generation device 57b, and the first detection result 51 and the second detection result 52 are synchronized for analysis. It can be generated as data 53 . As a result, detection results of the microplasma 19 at the same time by different methods can be obtained with high accuracy.

Another factor is that, as described above, in the first detector 20, a predetermined time. For example, if there is a change in the state of the microplasma 19 while scanning the mass spectrum, the mass spectrum 51c obtained at time tn reflects the state of the microplasma 19 at time tn. may not. On the other hand, if there is no change in the second detection results 52a to 52c while scanning the mass spectrum, the mass spectrum 51c obtained at time tn reflects the state of the microplasma 19 at time tn. can be guaranteed. In order to ensure the reliability of the mass spectrum 51, the generation device 57b may synchronize all of the second detection results 52 while the mass spectrum 51 is being acquired and generate the data 53 for analysis. The generator 57b verifies that all the second detection results 52a-52c are the same while acquiring the mass spectrum 51, and generates the mass spectrum 51c when all the second detection results 52a-52c are the same. may be generated as analysis data 53 in synchronization with the second detection result 52c, and the mass spectrum 51c may be discarded when the conditions are not met. The generation device 57b may store the analysis data 53 generated in this manner in the memory 55, or may output the data to an external server or process controller 105 via the communication device 57d.

That is, the gas analyzer 1 includes a sample chamber 12 that generates a common plasma 19 that serves as an ion source and a light source separately from the process 102, and the sample chamber 12 has a preliminarily fixed route. 1 detector 20 and a second detector 80 . Therefore, the serial first detection result 51 and the parallel second detection result 52 for the common plasma 19 generated in the sample chamber 12 can be synchronously obtained and linked by the generator 57b. can be generated as analysis data 53 and output. Therefore, by checking the variation of the second detection result 52 acquired in parallel during the time interval during which the first detection result 51 acquired serially is obtained, the first detection result 51 is information from the plasma 19 maintained under the same conditions, for example, the process under the same conditions, and a more reliable analysis result can be obtained.

Also, minute microplasma 19 is generated in the sample chamber 12 of the gas analyzer 1 . For this reason, the volume of the common ion source and light emission source that are the detection targets of the first detector 20 and the second detector 80 can be reduced, the bias in the plasma can be reduced, and the first detector for the same target can be reduced. A detection result 51 and a second detection result 52 can be obtained. Furthermore, it is also possible to limit the serially obtained mass spectrum 51 to a region of interest (ROI) 51r. It is also possible to obtain the result 51 serially over time. That is, as shown in FIG. 2, the first detection result 51 may include the mass spectrum 51c, and particularly only the mass spectrum 51c limited to the ROI 51r. Therefore, while confirming a wide range of information, it is possible to obtain a more accurate analysis result for the ROI even at short time intervals.

The PLC 50 further includes a plasma generation control device 57a that manages the generation state of the microplasma 19 via the plasma controller 16, and the filter 25 of the first detector 20 so that a mass spectrum in the desired ROI range can be obtained. It may include a ROI control device 57c for control, and a communication control device 57d for communicating with the process controller 105 and/or an external server or the like by wire and/or wireless.

The PCL 50 further includes an analysis device (analysis unit, analysis function) 70 that analyzes components (elements) contained in the sample gas 9 based on analysis data 53 including the first detection result 51 and the second detection result 52. may contain The analyzer 70 analyzes the sample gas 9 based on the first detection result 51 and the second detection result 52 synchronized with the first detection result 51 with a time interval defined by the gas analyzer 1. A first analyzer (first analysis unit) 71 may be provided.

As described above, in terms of spectral interference, the first detector (MS) 20 cannot separate elements (components) having the same mass-to-charge ratio m/z, while the second detector (OES ) 80 is difficult to separate elements (components) with spectra having the same or close frequencies. Conversely, components that cannot be separated in the first detection result 51 of the first detector 20 can be separated in the second detection result 52 of the second detector 80, and can be separated in the second detection result 52 of the second detector 80. Components that cannot be separated in the detection result 52 may be separated in the first detection result 51 of the first detector 20 . Furthermore, in the analysis apparatus 1 of this example, analysis data 53 is obtained by combining the first detection result 51 and the second detection result 52 which are temporally synchronized and highly reliable. Therefore, in the first analyzer 71, by cooperatively analyzing these data, it becomes possible to analyze the components of the sample gas 9 with higher accuracy.

The analyzer (cooperative control module) 70 outputs the detection result 51 of the first detector 20 and the detection result 52 of the second detector 80 in parallel, or at a time interval defined by the gas analyzer 1 . is provided to acquire the processed analysis result. In this process, the gas analyzer 1 includes an electron ionizer 15 in addition to the sample chamber 12, so the following processing methods (processing modes) may be selected. A second analyzer 72 may be provided which selects one of the modes M1, M2 and M3 for analysis.
(1) Detection of ionized components in the plasma 19 by the first detector 20 and emission analysis by the second detector 80 are performed in parallel (first mode, M1).
(2) The first detector 20 detects components by ionizing the gas derived from the plasma 19 with the electron ionization device 15, and the second detector 80 performs emission analysis in parallel (second mode, M2).
(3) detection of components by ionization by the electron ionizer 15 of the sample gas 9 supplied via the sample input 3b, not via the plasma 19, by the first detector 20 and by the second detector; Emission analysis of the plasma 19 by 80 is performed in parallel (third mode, M3).
By selecting or combining these processes, the component, state, concentration of each component, time change, etc. of the sample gas 9 can be accurately measured.

Note that except for the third mode, the sample input 3b is closed by the upstream valve 5b. Further, when the inside of the process chamber 101 has a negative pressure (vacuum) to the extent that it is difficult to generate the plasma 19, the sample input 3a is closed by the upstream valve 5a, and the sample gas 9 is supplied from the sample input 3b. may be ionized by the electron ionization device 15. In this case, no microplasma 19 is formed, so the detection result 52 by the second detector (OES) 80 is not obtained.

A process monitor (process monitoring device, process monitoring system) 100 is a process controller (process controller) 105. The process controller 105 may have computer resources such as a CPU and memory, and may be operated by a control program (program product) 109 . The process controller 105 may include an analysis device 70 having a common configuration with the PLC 50, and receives analysis data 53 from the gas analysis device 1, analyzes the sample gas 9, and performs 1 Or it may control multiple processes 102 .

The process controller 105 has a device (endpoint controller) 110 for determining the endpoint of at least one plasma process 102 from the results of detection (measurement) of the sample gas 9 containing by-products of the plasma process by the gas analyzer 1. Including equipment. At least one plasma process 102 may include at least one of etching, film formation, and cleaning. In this process monitor 100 , a plasma 19 is generated independently of the process chamber 101 in the sample chamber 12 controlled by the gas analyzer 1 , so that the component by the first detector (mass spectrometer, MS) 20 is detected. and the detection of the component by the second detector (OES) 80 can be synchronously correlated with a high degree of accuracy, and with a high degree of accuracy the by-products of the process 102 can be qualitatively identified, not just their presence or absence. analysis (analysis) can be performed. Therefore, the process controller 105 can appropriately control the plasma process 102 based on the analysis.

FIG. 3 is a flow chart showing an overview of how the process controller 105 controls the plasma process 102 . At step 121, process 102 in process chamber 101 is initiated. Simultaneously with this, or before or after this, in step 122 the process controller 105 initiates the analysis of the sample gas 9 by the gas analyzer 1 . In the gas analyzer 1, in step 123, the components of the plasma 19 in the sample chamber 12 are detected by the first detector (MS) 20 and the second detector (OES) 80, and the first The detection result 51 and the second detection result 52 are synchronized to generate related analysis data 53 . In the second detection result 52, information on a wide range of components can be obtained from the emission spectra obtained collectively and in parallel. In the first detection result 51, only the mass spectrum (MS) limited to the region of interest (ROI) can be acquired, and highly accurate and highly sensitive information can be obtained.

At step 124 , the first analyzer 71 analyzes the components of the sample gas 9 based on the analysis data 53 . When it is determined in step 125 that the measurement mode needs to be switched, in step 126 one of the first mode (M1), second mode (M2) and third mode (M3) is selected. You may

In step 127, the endpoint controller 110 of the process controller 105 determines the status and termination time of the process 102 based on the analysis results of the sample gas 9. When the conditions for terminating the process 102 are met, in step 128 the process End 102. The end of the process 102 may be determined by the endpoint controller 110 based on the detection result of the by-product of the plasma process 102 by the gas analyzer 1 . Thereafter, preparations are made to begin processing the next process, and the sequential process can be repeated to produce the product.

4 shows a different example of the process monitoring device 100. FIG. This process monitoring device 100 comprises a different example of gas analyzer 1 . In this gas analyzer 1 , the spectroscopic analysis unit 85 of the second detector 80 is arranged so as to be directly connected to the translucent dielectric wall structure 12 a of the sample chamber 12 . Therefore, the light from the plasma 19 in the sample chamber 12 can be spectroscopically analyzed without passing through the optical fiber, and the spectroscopically analyzed results can be obtained with higher accuracy. Further, by arranging the spectroscopic analysis unit 85 adjacent to or coaxially with the wall 12a to which the RF for generating plasma is supplied, the plasma 19 is generated so as to treat the inner surface of the wall 12a with the plasma 19. can generate Therefore, it is possible to prevent a situation in which the inner surface of the wall 12a is contaminated with derivatives of the plasma 19 and the emitted light becomes difficult to see.

This gas analyzer 1 comprises a first path 151 for supplying an ionized gas flow (ion flow) 17 from an opening 18 provided at one end of a sample chamber 12 to a first detector 20; and a second path 152 for supplying light from the other end of 12 for spectroscopic analysis by a second detector 80 . Light for spectroscopic analysis can be obtained from the opposite direction from which the ion stream 17 flows, suppressing unexpected variations in the second detection result 52 of the second detector 80 .

FIG. 5 shows yet another example of the process monitoring system 100. This process monitoring system 100 includes yet another example of gas analyzer 1 . The sample chamber 12 of this gas analyzer 1 is cylindrical with a translucent dielectric side wall 12b and is a collector for guiding light via an optical fiber 82 to the spectroscopic analysis unit 85 of the second detector 80. An optical element 81 is attached to the side wall 12b. Therefore, this gas analysis apparatus 1 is capable of generating a flow of ionized gas (ion flow ) 17 and a third path 153 that provides light for spectroscopic analysis by the second detector 80 in a direction orthogonal to the first axis 155 of the sample chamber 12. . A third path 153 allows lateral access to the plasma 19 generated in the cylindrical chamber 12 . Therefore, the second detector 80 can perform emission analysis (spectroscopic analysis) using the emission of the atomized sample at the center of the plasma 19, and can obtain the detection result 52 with higher accuracy. .

The place where the spectroscopic analysis unit 85 is arranged or the place where the optical fiber 82 is attached to obtain the light emission of the plasma 19 is not limited to the above.

The above includes a sample chamber with a dielectric wall structure into which only the sample gas to be measured flows; A gas analyzer is disclosed that has a plasma generation mechanism that generates plasma and an analysis unit (sensor group) that analyzes a sample gas via the generated plasma. The analysis unit includes a first analyzer (first detector), for example a mass spectrometer, for filtering ionized gases in the plasma, and a second analyzer (first detector) for spectroscopically analyzing the ions in the plasma in the sample chamber. 2 detectors), such as an emission spectrometer. This analyzer can spectroscopically analyze the ion species and concentration of the plasma, which is the ion source of the first analyzer, by the second analyzer. Thus, a common ionized sample can be analyzed by different methods simultaneously in parallel or within a limited time interval (latency) within the gas analyzer, and the analysis results of those different methods can be combined in one analyzer. can be obtained in real time as the analysis result of That is, the analysis unit acquires the analysis results obtained by processing the analysis results of the first analyzer and the analysis results of the second analyzer in parallel or by providing the time interval specified by the gas analyzer. A third analyzer may be included that performs. In other words, the results of capturing the ionized gas in the plasma in the sample chamber without time lag by different analysis methods are compared, and the composition and concentration of the sample gas are analyzed with high accuracy, including temporal fluctuations. can.

Since microplasma is formed in the sample chamber, the size of the light source is sufficiently small for the target of emission spectroscopic analysis, and stable analysis results can be obtained. The second analyzer may comprise a unit for receiving light from the plasma in the sample chamber through a highly translucent dielectric wall structure, the inner surface of which is constantly refreshed by the plasma. Therefore, deterioration of analysis performance due to contamination can be suppressed. Furthermore, the second analyzer may be a spectroscopic analyzer connected to the sample chamber via an optical fiber, and in order to eliminate the effects of the optical fiber, the second analyzer emits light from the sample chamber without the optical fiber. may include a spectroscopic analyzer to obtain The first analyzer may include an electron ionization unit that produces electrons for ionizing the sample gas.

Further disclosed above is a process monitoring system having a gas analyzer. A process monitoring system is an example of a system having a gas analyzer and a process chamber in which a plasma process is performed and in which a sample gas is supplied to the gas analyzer.

The above further discloses a method of analyzing the components of a sample gas with a gas analyzer. This method obtains the analysis results obtained by processing the analysis results of the first analyzer and the analysis results of the second analyzer in parallel or by providing a time interval defined by the gas analyzer. including. Even if there are components that cannot be separated by mass spectrometry due to the same charge ratio, high-precision analysis results can be obtained by analyzing the mass spectrometry results by adding ionization types obtained by spectroscopic analysis. There are many effects that can be obtained by collaborating with analysis. If the first analyzer includes an electron ionization unit that generates ions for ionizing the sample gas, it may include the following measurement method. (1) Analysis of the ionized gas in the plasma by the first analyzer and analysis of the gas in the plasma by the second analyzer are performed in parallel. (2) The first analyzer ionizes the gas derived from the plasma by the electron ionization unit, and the second analyzer analyzes the gas in the plasma in parallel. (3) The analysis of the gas ionized by the electron ionization unit by the first analyzer and the analysis of the gas in the plasma by the second analyzer are performed in parallel without passing through the plasma.

Further disclosed above is a method of controlling a system having a process chamber for performing a plasma process. The system has an analyzer as described above, only a sample gas from the process chamber flows into the sample chamber, and the method comprises a plasma process performed in the process chamber based on the measurement results of the gas analyzer. including controlling

In the above description, an example of a mass filter adopting a quadrupole type as the filter 25 of the first detector 20 is described, but this filter 25 may be an ion trap, a Wien filter, or another type of filter. can be a type.

Also, while specific embodiments of the present invention have been described above, various other embodiments and modifications can be envisioned to those skilled in the art without departing from the scope and spirit of the present invention. Such other embodiments and variations are covered by the following claims and it is intended that the invention be defined by the following claims.

Claims

a sample chamber with a dielectric wall structure and into which the sample gas to be measured flows;
a plasma generation mechanism for generating plasma in the depressurized sample chamber by an electric field and/or a magnetic field through the dielectric wall structure;
a gas input device configured to flow only the sample gas from a process into the sample chamber;
a first detector that filters ionized gas in the generated plasma to detect components in the plasma;
and a second detector capable of analyzing emission of ions in the plasma in the sample chamber and outputting a second detection result synchronized with the first detection result of the first detector. Device.
In claim 1,
Data for analysis in which the first detection result including the mass spectrum acquired by time division is associated with the second detection result including the emission spectrum that can be compared in synchronization with the first detection result. A gas analyzer having a generator for generating.
In claim 2,
A gas analyzer, wherein the mass spectrum comprises a mass spectrum limited to a region of interest.
In any one of claims 1 to 3,
A first analyzer for analyzing the sample gas based on the first detection result and the second detection result synchronized with the first detection result with a time interval defined by the gas analyzer. , a gas analyzer.
In any one of claims 1 to 4,
a first passageway supplying the ionized gas from one end of the sample chamber to the first detector;
and a second path for providing light for spectroscopic analysis by said second detector from the other end of said sample chamber.
In any one of claims 1 to 4,
a first passageway supplying the ionized gas to the first detector from one end of the sample chamber along a first axis;
and a third path for providing light for spectroscopic analysis by said second detector in a direction orthogonal to said first axis of said sample chamber.
In any one of claims 1 to 6,
the dielectric wall structure includes at least one of quartz, aluminum oxide and silicon nitride;
A gas analyzer, comprising a light guide that directs light from the plasma in the sample chamber through the dielectric wall structure to the second detector.
In any one of claims 1 to 7,
A gas analyzer, wherein the second detector includes an emission analyzer connected to the sample chamber via an optical fiber.
In any one of claims 1 to 8,
The gas analyzer, wherein the sample chamber has a total length of 1-100 mm and a diameter of 1-100 mm.
In any one of claims 1 to 9,
The gas analyzing apparatus, wherein the plasma generation mechanism includes a mechanism for generating plasma by at least one of dielectric coupling plasma, dielectric barrier discharge, and electron cyclotron resonance.
In any one of claims 1 to 10,
A gas analyzer comprising an exhaust system for evacuating the sample chamber.
In claim 11,
The gas analyzer of claim 1, wherein the exhaust system includes a first exhaust path for exhausting the sample chamber from the sample chamber bypassing the first detector.
In any one of claims 1 to 12,
A gas analyzer, comprising an electron ionizer for electron ionizing gas from said sample chamber and/or sample gas from said gas input device for supply to said first detector.
In claim 13,
a first mode in which detection of components in the plasma by a first detector and emission analysis by the second detector are performed in parallel;
a second mode in which the first detector detects components by ionizing the gas derived from the plasma by the electron ionization device and the emission analysis is performed by the second detector in parallel; ,
A third method in which detection of components by ionizing the sample gas from the electron ionization device without the plasma is detected by the first detector, and the emission analysis is performed by the second detector in parallel. A gas analyzer having a second analyzer that selectively performs a mode of
A process monitoring device comprising the gas analyzer according to any one of claims 1 to 14.
a gas analyzer according to any one of claims 1 to 14;
a process chamber in which a plasma process is performed, wherein the gas analyzer is supplied with the sample gas.
In claim 16,
A system comprising a process controller for controlling at least one plasma process performed in said process chamber based on measurements of said gas analyzer.
In claim 17,
The system, wherein the process control device includes a device for determining the endpoint of the at least one plasma process from measurements by the gas analyzer of the at least one plasma process by-product.
A method of controlling a system having a gas analyzer, comprising:
The gas analyzer comprises a sample chamber having a dielectric wall structure, into which a sample gas to be measured flows, and the sample chamber decompressed by an electric field and/or a magnetic field via the dielectric wall structure. a plasma generation mechanism for generating a plasma within; a gas input device configured to allow only said sample gas from a process to flow into said sample chamber; and filtering ionized gases in said generated plasma to A first detector that detects components in the plasma, and a second detector that outputs a result of analyzing the emission of ions in the plasma in the sample chamber,
The method includes synchronously outputting a first detection result of the first detector and a second detection result of the second detector.
In claim 19,
The synchronous output includes the first detection result including a mass spectrum acquired in a time division manner, and the second detection result including an emission spectrum that can be compared in synchronization with the first detection result. A method comprising outputting in association with and.
In claim 20,
The method, wherein the mass spectrum comprises a mass spectrum restricted to a region of interest.
In any of claims 19-21,
analyzing the sample gas according to the first detection result and the second detection result synchronized with the first detection result with a time interval defined by the gas analyzer. .
In any of claims 19-22,
the gas analysis device includes an electron ionization device that electron ionizes gas from the sample chamber and/or sample gas from the gas input device and supplies the gas to the first detector;
The method includes a first mode in which detection of components in the plasma by a first detector and emission analysis by the second detector are performed in parallel;
a second mode in which the first detector detects components by ionizing the gas derived from the plasma by the electron ionization device and the emission analysis is performed by the second detector in parallel; ,
A third method in which detection of components by ionizing the sample gas from the electron ionization device without the plasma is detected by the first detector, and the emission analysis is performed by the second detector in parallel. A method comprising: selecting and performing a mode of
In any of claims 19-23,
The system comprises a process chamber for performing a plasma process, the process chamber being capable of supplying a sample gas to the gas analyzer via the gas input device;
The method is
and controlling a plasma process performed in the process chamber based on detection results of the gas analyzer that generated a plasma independent of the process chamber in the sample chamber.
In claim 24,
The method of claim 1, wherein controlling the plasma process includes determining an endpoint of at least one plasma process from detection by the gas analyzer of the at least one plasma process by-product.
In claim 25,
The method, wherein the at least one plasma process includes at least one of etching, film formation, and cleaning.
A program for controlling a system by a computer by a method of controlling a system having a gas analyzer according to any one of claims 19 to 26,
A program comprising instructions for performing the method of any of claims 19-26.